Four kinds of surfactants were used to increase accessibility of pyrene and cadmium (Cd) in simulated pyrene, Cd, and pyrene-Cd soils in this study. Tea saponin (TS) at 40 mg L⁻¹groups (exchangeable fraction of Cd and bioaccessible fraction of pyrene were 8.96 and 36.93 mg kg⁻¹) showed more preferable potential application in improving solubilization capability than other surfactants. The morphology of Cd was transformed from Fe-Mn oxides (8.86 to 7.61 and 8.67 to 7.99 mg kg⁻¹in Cd and pyrene-Cd soil) and associated to carbonates fractions (4.46 to 4.36 and 4.28 to 4.36 mg kg⁻¹in Cd and pyrene-Cd soil) to exchangeable fraction with adding TS. These two morphological changes were important processes in the solubilization of Cd. The morphology of pyrene was transformed from associated fraction (72.15 to 61.95 and 71.02 to 63.48 mg kg⁻¹in pyrene and pyrene-Cd soil) to bioaccessible fraction (26.66 to 33.71 and 26.91 to 36.93 mg kg⁻¹in pyrene and pyrene-Cd soil) with adding TS. This morphological transformation was important in the improving of solubilization capacity of pyrene. In contrast, the solubilization of pyrene was promoted in the presence of Cd in pyrene-Cd soil (the bioaccessible fractions were 33.71 and 36.93 mg kg⁻¹in pyrene and pyrene-Cd soil), but the solubilization of Cd was hindered in the presence of pyrene (the exchangeable fractions of Cd were 8.86 and 8.67 mg kg⁻¹in Cd and pyrene-Cd soil). These findings will be beneficial for application of surfactants in soil remediation.

A geochemical analysis and modelling was carried out to investigate the As occurrence and release in groundwater from two different geological environments on Lesvos Island: (i) the volcanic area of Mandamados (ignimbrite of rhyolithic to rhyodacitic composition) and (ii) the metamorphic area of Tarti (schists and marbles) that comprises the geologic basement under ignimbrite. Seven sampling campaigns were conducted between October 2010 and October 2011, including 65 groundwater samples from 11 wells and springs. Chemical analyses showed As concentrations exceeding the 10-μg/L national drinking water limit in 46 % of the samples from Mandamados. Groundwater composition in Mandamados evolved from Ca-HCO₃ type, to mixed type and finally to Na-Cl type along the groundwater flow direction, indicating the contribution of ion exchange in groundwater chemical composition, while Ca-HCO₃ type waters were observed in the Tarti area. Arsenic speciation analysis showed that As(V) was the main species in all samples, indicating that As was released under oxidizing conditions. Statistical analysis suggested silicate weathering as the prime mechanism of As release in groundwater in both cases, while, in the Tarti area, carbonate dissolution may represent a secondary mechanism which could be related to the observed relatively low As concentrations in the region. In both areas, pH-related desorption of As, primarily from Fe mineral phases, was found to be the most important factor controlling the mobilisation of As, while the contribution of the redox control to As release in groundwater was generally found to be less significant.

During the extraction of coal bed methane (CBM), entrapped in the deep layers of different coal beds, large amount of coal bed water (CBW) is also simultaneously released. The quality of this water is generally very poor which may often contaminate the adjoining soil environment adversely. In the present study, some major changes occurring in CBW-contaminated soils were assessed with relation to nearby non-affected soils. The CBW was found to be moderately saline and highly alkaline in nature with high sodium absorption ratio (SAR) values. Contamination with this water affected the soil environments substantially resulting in significantly increased pH and exchangeable sodium percentage (ESP) in the affected soils thus rendering the soils unsuitable for undertaking common agricultural practices. However, in spite of moderately high electrical conductivity values of this contaminating water, the resultant increments in salinity status of the soils were not observed to reach near the critical level. This behaviour was attributed to light texture of these soils which probably helped in leaching of a part of the soluble salts. Some microbial properties as well as availability of nitrogen and phosphorus were also found to decline in these CBW-affected soils. The study showed that utmost care needs to be exercised before release of CBW during extraction of CBM. In case of any contamination to nearby arable soils, suitable amendment practices for alkaline soils need to be adopted to mitigate the adverse effects of such water on soil environment.

The elimination of five selected emerging contaminants (1-H-benzotriazole, N,N-diethyl-m-toluamide (DEET), chlorophene, 3-methylindole, and nortriptyline HCl) dissolved in different water matrices (surface water and secondary effluents) was carried out by sequential membrane filtration and chemical oxidation processes. First, a membrane filtration (ultrafiltration (UF) or nanofiltration(NF)) pre-treatment was conducted, and both permeate and retentate were afterwards treated by chemical oxidation, using ozone or chlorine. The application of UF and especially of NF provided a large volume of permeate, whose quality can be improved by a chemical treatment to completely remove residual contaminants except 1-H-benzotriazole. Chlorination and especially ozonation have demonstrated to be effective for the reduction of emerging contaminants in the concentrated stream, thus generating an effluent that might be recycled to the activated sludge treatment in the wastewater treatment plants (WWTP). In a second group of experiments, a chemical oxidation pre-treatment (by using ozone, chlorine, O₃/H₂O₂, ultraviolet (UV) radiation, or UV/H₂O₂) was applied followed by a nanofiltration process. Results of removals and rejection coefficients for the emerging contaminants showed that the chemical pre-treatment exerted a positive influence on the subsequent NF process, not only in terms of ECs removal but also of dissolved organic carbon content (DOC) reduction. While global removals higher than 97 % were reached for DEET, chlorophene, 3-methylindole, and nortriptyline HCl, lower values were obtained for 1-H-benzotriazole, especially for chlorine pre-treatment and in those water matrices with high content of natural organic matter. Therefore, both sequential treatments are promising to remove the selected micropollutants while reducing the chlorine doses needed to achieve final water disinfection.

The feasibility of using cell-free extracts of nitrifying sludge to treat synthetic wastewater containing 4-methylphenol and ammonium was examined. Nitrifying cells were broken by sonication and encapsulated into calcium alginate. Cell-free extracts (CFE) of nitrifying sludge oxidized 4-methylphenol threefold faster than whole-cells, but CFE were not able to oxidize ammonium. The CFE encapsulated into calcium alginate (CFEA) displayed partial nitrification and 4-methylphenol oxidation. Five hours was enough to oxidize 100 % of ammonium and 4-methylphenol, at volumetric rates of 20.80 mg N/L h and 42.86 mg C/L h, respectively. It is inferred that an interaction between the CFE and calcium alginate resulted in the protection of the enzymes.

Uranium soil depollution is of great concern as, like any other radionuclide, it may accumulate in time and generate a negative impact on human health. There are several decontamination technologies, among these the acid washing still in use for its simplicity and low cost. Though a classical method, it still can be improved by using the best operating conditions to increase the decontamination degree. The present study aims to propose an optimization approach based on experimental design. The investigation takes into account the main operating parameters (duration, temperature, and pH) and the soil characteristics (texture and organic matter content). This work presents an “ex situ” uranium-contaminated soil treatment using a 0.1 M H₂SO₄solution with pulp density of 0.5. The experiments followed a 2³factorial design for the evaluation of factors and interaction effects. The factors’ influence differed from one type of soil to another. The 2³experiment was augmented using a non-central composite design that allowed the formulation of a second degree model for the response surface. The best values for the operating parameters were identified using optimization procedures. Statistical modelling and optimization were performed in Matlab® v7.7. The results obtained proved that the soil type is very important for selecting better operating conditions. These improvements determined an increased decontamination degree of up to 10–13 % compared with standard operating conditions that were considered as central point in the experimental plan.

For many years, atmospheric mercury has been perceived as a global pollutant. Transport of mercury compounds in the atmosphere and its deposition on the earth’s surface is an important issue that requires knowledge regarding the circulation of the various forms of this metal between environmental components. There are many numerical models that can be used to study and image this phenomenon. These models are based on data concerning mercury emission sources, concentrations of this contaminant on modelling areas and meteorological data to assess air mass inflow on a regional and global scale. A method to assess mercury deposition fluxes on a local scale based only on stream intensity analysis of mercury is proposed in this study. Mercury deposition fluxes (bulk) that were assessed by the MDC method at the Zloty Potok station (regional background station for the Silesian Agglomeration) varied from 22.8 μg · m⁻² · year⁻¹ (an 8-month period in 2013) to 54.2 μg · m⁻² · year⁻¹ in 2012. Developing procedures to estimate the mercury deposition coefficient (MDC) is useful in areas where only meteorological parameters and mercury concentrations in the atmospheric air are measured. The obtained deposition coefficient values enable quantification of a selected pollutant concentration and its potential impact resulting from deposition.

Activated carbon is investigated as adsorptive barrier for organic micropollutants (OMP) within the Berlin water cycle. In a pilot plant using granular activated carbon (GAC) as upper layer in dual-media filtration, OMP concentrations in treated wastewater could be reduced without any negative impact on filtration efficiency. OMP breakthroughs occurred after shorter runtimes than estimated according to isotherm experiments with powdered activated carbon (PAC). Batch adsorption tests comparing the used GAC to new GAC showed that the capacity of the used GAC was not exhausted, indicating that besides direct site competition, pore blocking is also responsible for the poor GAC performance. A pilot plant application of PAC of the same type as GAC showed significantly higher OMP removals at lower dosages, taking advantage of immobilization of PAC particles in the filters. Both PAC and GAC applications can be integrated into tertiary wastewater treatment without significant constructional changes.

The adsorbents (such as hydrous ferric oxides, HFO) generated in the electrocoagulation (EC) processing with iron electrodes are able to remove effectively inorganic arsenic (As) present in underground water. A characterization of the HFO phases produced during the arsenic removal by the EC process from low and high arsenic concentration, by using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM), is presented. The main HFO phase produced by this process is lepidocrocite (γ-FeOOH), and that the sorption of arsenic by this solid-state phase formed as part of the EC process was effective in removing arsenic from aqueous solution.

From a storm water management perspective, not all pavements are equivalent. Pavement type can impose a strong influence on pollutant wash-off dynamics. Pollutant loads from pavement wash-off are affected by the pavements’ physical and chemical composition. However, there is a dearth of information regarding how pavement type influences atmospherically deposited pollutant loads in storm water. Therefore, experimental impermeable and permeable asphalt and concrete boards were deployed in a residential area in Christchurch, New Zealand, to quantify the influence of pavement type on storm water pollutant dynamics. Each pavement type had four replicate systems elevated 500 mm from the ground at a 4° slope. Wash-off from the pavements was collected and analysed for total suspended solids and metals (Cu, Pb, and Zn) from June to August 2014. Results show that Cu and Zn loads were lower from the concrete pavements than the asphalt pavements because the carbonates and hydroxides within the concrete adsorbed Cu and Zn. Run-off from the impermeable asphalt had the highest loads of Zn, which was attributed to Zn leaching from the asphalt. Infiltrate from permeable asphalt provided little/no retention of Cu and Zn, due to the low pH of the infiltrate causing Cu and Zn to partition into the dissolved phase and leach through the pavement. Total suspended solid (TSS) and Pb loads were the highest in run-off from the impermeable concrete, which was attributed to the smooth surface enabling particulates to be easily mobilised. TSS and Pb loads were the lowest from the permeable pavement due to the permeable material filtering out particulates.